29 May 2010

The latest VLF receiver

Here is a picture of the latest version of my VLF 1-2kHz receiver for use with my 80cm loop. The version before this (Wednesday) had one less Sallen-Key active high pass filter and was able to copy my 4W grounded electrode transmissions "by ear" at 0.5kms. This latest version now has 2 sections of 50Hz active high pass filtering so should offer better S/N at the limit of range. The audio above 2kHz is attenuated by the passive LPF.

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